Display devices present a variety of image information, including image information captured by digital video or still photo cameras, image information produced by software applications, video games, or other programs, image information obtained from video or still photo archives, or image information obtained from broadcast or streaming media. A display device may be integrated with, coupled to, or otherwise associated with a variety of devices, such as desktop or laptop computers, computer workstations, mobile devices such as personal digital assistants (PDAs) or mobile telephones, and dedicated viewing stations such as televisions. A display device may comprise a liquid crystal display (LCD), a cathode ray tube (CRT) display, a plasma display, a projection display, or the like.
A display device maintains an inherent maximum resolution limited by the number of pixels capable of displaying the image information. In general, displays may produce a range of image resolution at or below the inherent maximum resolution. If the image information defines values for less than all of the display pixels, however, the device may scale the image information upward to a larger resolution. For example, a display device may produce additional pixels by interpolation to scale the image information to a larger format. As displays become larger, image scaling becomes increasingly important. For mobile applications, even though users may desire larger displays, channel limitations tend to reduce the amount of image information that can be transmitted to a mobile device, resulting in smaller format images. Hence, to consistently achieve larger formats, image upscaling is desirable for mobile applications.
Many techniques currently exist to interpolate pixel values to achieve image upscaling. Common interpolation techniques include bilinear interpolation, bicubic interpolation, cubic spline interpolation, and new edge directed interpolation (NEDI). While all of the above interpolation techniques are effective in upscaling the image information, artifacts such as blurring may result. In addition, some techniques, such as NEDI, may require complex calculations that consume an excessive amount of system resources, especially in small mobile devices. Further, some existing interpolation techniques may be unsuitable for color image information, resulting in color bleeding or other artifacts. In general, upscaling is challenging because more pixels have to be created by interpolating existing but limited information, possibly leading to blurriness in the output.